Methods of Modifying Surface Coverings to Embed Conduits Therein

ABSTRACT

Methods of modifying surface coverings to embed conduits therein to collect solar heat energy including grinding away a portion of the surface covering, installing a network of conduits in the recess and filling the recess to cover the conduits with a material capable of transferring heat from solar radiation to the conduits and a method for modifying a surface covering to embed conduits therein to collect solar heat energy including softening the surface covering, forming a channel in the softened surface covering, pressing a conduit into the channel and filling the channel with thermal conductive material to cover the conduit.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

This application claims priority from prior provisional patentapplication Ser. No. 61/138,143 filed Dec. 17, 2008, the entiredisclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention pertains to obtaining and using power/energy fromman-made structures including manufactured (paved) surfaces and, moreparticularly, modifying pre-existing surface coverings to createpower/energy in the form of heat obtained from solar radiation for usein the operation of energy conversion equipment, such as chillers, hotwater supplies, heat pumps, organic Rankine cycle engines formechanically generating electricity, water purification and distillationfor buildings and/or other facilities.

2. Brief Discussion of the Related Art

Surfaces and structures are heated by solar radiation during the courseof a typical sunny day. A typical asphalt or concrete surface has goodheat-absorbing properties, and the heat energy from such structures isnormally wasted and not utilized to its potential. Greater use of solarenergy is an environmental friendly way of meeting increasing energyneeds. In recent years, it has become increasingly evident that fossilfuels used to generate energy are finite and that their use is harmfulto the environment. Large paved surfaces increase surface temperatures.The National Oceanic and Atmospheric Administration's NationalGeophysical Data Center relative to highways, streets, buildings,parking lots and other solid structures, notes that the total pavedsurface area of the 48 contiguous states of the United States of Americaand the District of Columbia is approximately 43,480 square miles(112,610 km²). This same study further describes that 1.05% of theUnited States of America land area is constructed, impervious surface(83,337 km²) and 0.43% of the world's land surface (579,703 km²) isconstructed, impervious surface. China has more impervious surface areathan any other country (87,182 km²) but has only 67 m² of impervioussurface area per person, compared to 297 m² per person in the UnitedStates of America. Asphalt, concrete, bituminous roofs and otherhard-paved surfaces absorb heat making it unpleasant to walk on asidewalk in hot weather and increasing the strain on the airconditioning systems of buildings. Since hot air rises, the hot airtraps airborne pollutants, such as auto exhaust, close to the groundadding to complications for pedestrians. The Portland Cement Associationestimates that the “heat island effect” of concentrated areas of pavedsurfaces impervious to water increases the temperature of the pavedareas by average of three to eight degrees. The most extreme increasestake place in heavily paved areas, areas without shade, and areas pavedwith materials that don't reflect substantial light, such as asphalt.The heat island effect occurs in both small-town and urban commercialareas.

The organic Rankine cycle engine uses an organic, high molecular massfluid with a liquid-vapor phase change, or boiling point, occurring at alower temperature than the water-steam phase change. Accordingly,Rankine cycle heat recovery can be obtained from lower temperaturesources such as industrial waste heat, geothermal heat, solar ponds andthe like. Typically, the lower temperature heat is converted into usefulwork that can itself be converted into electricity.

Waste heat recovery is the most important development field for theorganic Rankine cycle engine, as well as for absorption/adsorptionchillers. Waste heat can be applied to heat and power plants (forexample a small scale cogeneration plant for a domestic water heater)and also can be applied to industrial and farming processes such asorganic products fermentation, hot exhausts from ovens or furnaces, fluegas condensation, exhaust gases from vehicles, inter-cooling of acompressor, and condenser of a power cycle.

As identified by the United States Environmental Protection Agency,developing urban areas modify their landscape. For example, solid andimpermeable buildings, roads, and other infrastructure replace permeableand moist fields and vegetation. These changes cause urban regions tobecome warmer than their rural surroundings, forming an “island” ofhigher temperatures in the landscape. These heat islands occur on thesurface and in the atmosphere. On a hot, sunny summer day, the sun canheat dry, exposed urban surfaces, such as roofs and pavement, totemperatures 50-90° F. (27-50° C.) hotter than the ambient air, whileshaded or moist surfaces—often in more rural surroundings—remain closelyaligned to ambient temperatures. Surface urban heat islands aretypically present day and night, but tend to be strongest during the daywhen the sun is shining. The EPA states that these elevated temperaturesfrom urban heat islands, particularly during the summer, can affect acommunity's environment and quality of life; the majority negative.These impacts include:

(1) Increased energy demand for cooling. Research shows that electricitydemand for cooling increases 1.5-2.0% for every 1° F. (0.6° C.) increasein air temperature, starting from 68 to 77° F. (20 to 25° C.),suggesting that 5-10% of community-wide demand for electricity is usedto compensate for the heat island effect. Peak electricity demand,instigated by the urban heat island, inevitably occurs on hot summerweekday afternoons when offices and homes are running cooling systems,lights, and appliances. The resulting demand for cooling can overloadsystems and require a utility to institute controlled, rolling brownoutsor blackouts to avoid power outages.(2) Elevated Emissions of Air Pollutants and Greenhouse Gases.Increasing energy demand generally results in greater emissions of airpollutants and greenhouse gas emissions from power plants. Higher airtemperatures also promote the formation of ground-level ozone.(3) Compromised Human Health and Comfort. Increased daytimetemperatures, reduced nighttime cooling, and higher air pollution levelsassociated with urban heat islands can affect human health bycontributing to respiratory difficulties, heat exhaustion, non-fatalheat stroke, and heat-related mortality. Excessive heat events, orabrupt and dramatic temperature increases, are particularly dangerousand can result in above-average rates of mortality. The Centers forDisease Control and Prevention estimates that from 1979-2003, excessiveheat exposure contributed to more than 8,000 premature deaths in theUnited States. This figure exceeds the number of mortalities resultingfrom hurricanes, lightning, tornadoes, floods, and earthquakes combined.(4) Impaired Water Quality. High pavement and rooftop surfacetemperatures can heat storm-water runoff. Tests have shown thatpavements that are 100° F. (38° C.) can elevate initial rainwatertemperature from roughly 70° F. (21° C.) to over 95° F. (35° C.). Thisheated storm-water generally becomes runoff, which drains into stormsewers and raises water temperatures as it is released into streams,rivers, ponds, and lakes. Water temperature affects all aspects ofaquatic life, especially the metabolism and reproduction of many aquaticspecies. Rapid temperature changes in aquatic ecosystems resulting fromwarm storm-water runoff can be particularly stressful, even fatal, toaquatic life.

There are four current strategies to mitigate the urban heat islandeffect:

(1) Increasing tree and vegetative cover over the general landscape;

(2) Creating rooftop gardens;

(3) Installing reflective roofs; and

(4) Employing cool pavement technologies (aggregate make-up).

Heat island mitigation is part of a community's energy, air quality,water, or sustainability effort. These activities may range fromvoluntary initiatives to policy actions, such as requiring cool roofsvia building codes. Most mitigation activities have multiple benefits,including cleaner air, improved human health and comfort, reduced energycosts and lower greenhouse gas emissions.

As an alternative to powering vehicles using the internal combustionengine, designers have experimented with batteries, fuel cells, andsolar panels. These experiments have been motivated, in large part, by aconcern that gases emitted by internal combustion engines could harmhumans by adversely affecting their environment. Motivated by theseconcerns, lawmakers have passed laws governing vehicle emissions.Accordingly, there is an ongoing need for sources of power that cansupplement or replace the internal combustion engine as a source ofpower for vehicles. For similar reasons, there is a need for alternativestationary sources of power that reduce harmful environmental effectsassociated with the combustion of fossil fuels.

With a growing concern over global climate change, scientists,lawmakers, and entrepreneurs are all seeking solutions. At the forefrontof this debate are new sources of power. These could provide analternative to fossil fuels, which release harmful greenhouse gases.

Similarly, in addition to clean energy sources, it is important not tooverlook methods to reduce the effects of global warming. Paving overvegetation allows more heat to be absorbed by the Earth's surface, andlater reradiated into the atmosphere. This is particularly true in areaswith heavy populations, roads and travel, where the necessity for pavingis largest. This gives way to the Urban Heat Island effect, which hasincreased the needs of air conditioning in cities like Los Angles byover 40% during the summer months.

SUMMARY OF THE INVENTION

Systems utilizing modified surface coverings formed in accordance withthe present invention use the heat absorbed by surfaces from incidentsolar radiation to produce energy in various forms. The systems can useembedded thermally conductive materials or fluid carrying pipes/conduitsin pavement as a structure to transfer heat for multiple uses. A heatedfluid will first be moved to a heat exchanger. The heat produced can beused for hot water for hotels, laundromats, car washes, pre-heating ofboilers, or chemical/industrial processes to name a few. The systems canalso produce electrical power through a low temperature generator suchas one powered by an organic Rankine cycle engine. Heat from the systemscan drive an absorptive or adsorptive chiller to produce an airconditioning or cooling system. The systems can be used in conjunctionwith or in series with another source, such as a Concentrated SolarPower system, to produce higher temperatures for more efficient powergeneration. Designs to improve efficiencies of the system include theuse of thermally conductive roadway aggregates, low emissivity coatings,and use of guardrails, bridges and other thermally conductive structuresas a heat source or heat transfer method. The system heat source can beused for pasteurization, distillation and the like therefore permittinguse for water purification.

The system can use the aggregate itself as the conductive materialinstead of another thermally conductive material that would not normallybe part of the HMA (hot mix asphalt). If thermally conductive materialsare not available locally, they can be purchased and transported fromnon-local sources. A conductive layer can be put down within the surfaceto reduce the costs of what may be a more expensive aggregate material.This serves to increase the heat travel to essential regions forpractical conversion. The heat collected from such systems can be usedto run a thermal cycle engine (e.g., an organic Rankine cycle engine), aheat pump, or a chiller. The heat energy is used to heat a fluid such aswater or refrigerant that is used in such equipment. This provides ameans of converting raw heat into more tangible or useful applications.A network of pipes/conduits can lead from the source (manufacturedsurface covering, such as a paved surface or structure) to the drain(energy conversion unit or heat exchanger). The pipes/conduits can beinstalled in a number of ways and can be made of various materials andgeometries. Regardless of how they are installed, the commonality is theintention of removing heat from the pipes/conduits. The system can beused in conjunction with other energy sources, namely geothermal,photovoltaic, and biofuel. Additional uses include the use of thesesystems as a means to purify, decontaminate, desalinate, and cleanwater. Heat can be derived from buildings and roadway structures.

A low temperature source such as geothermal, flat plate or pavedsurface, (roadway power system) can have its temperatures bolstered by asupplementary heating source. This source could be solar driven, e.g.concentrated solar power (CSP), parabolic, dish or a combustion engine,using gas, oil, or another incendiary source. These elevatedtemperatures allow use for agriculture, water purification anddesalinization, biofuels, hydrogen generation and increased efficiencieswith existing methods of energy conversion.

When using the system to generate electricity, it will relieve part ofthe dependency on ‘dirty’ power by bringing a new source of ‘green’electricity generation. It will also help reduce loads on the electricaltransmission systems since it will act as distributed generationon-site.

One aspect of the present invention is to provide a method for modifyingor retrofitting an existing surface covering to embed conduits thereinproviding a heat recovery structure.

In another aspect, the method of the present invention permitsmodification or retrofitting of a man-made covering on the earth'ssurface to have fluid carrying conduits embedded therein with a purposeof delivering solar heated fluid to an energy conversion device. Thecovering can be any existing surface such as a paved surface, a roadway,a road shoulder, a parking lot, a sidewalk, a path, a track, aracetrack, a sports field, a roadway divider, a railroad track, a patio,a roof, shingle or siding for buildings, tarmac, and the like.

In another aspect, the present invention permits the use of existingstructures and surface coverings for collection by modifying orretrofitting such structures and surface coverings, particularlypavement and synthetic turf by embedding a conduit network therein tocollect solar heat energy.

A method according to the present invention for modifying a surfacecovering to embed conduits therein to collect solar heat energy includesthe steps of grinding away a portion of the surface covering to form arecess therein, installing a network of conduits for carrying heatedfluid in the recess and filling the recess to cover the conduits with amaterial capable of transferring heat from solar radiation to theconduits to heat the fluids.

The present invention also relates to a method for modifying a surfacecovering to embed conduits therein to collect solar heat energyincluding the steps of softening the surface covering, forming a channelin the softened surface covering, passing a conduit into the channel andfilling the channel with thermal conductive material to cover theconduit.

Various aspects, advantages and benefits of the present invention willbecome apparent from the following description taken in conjunction withthe drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a surface covering, with parts cut away,with a network of conduits disposed in the recess in accordance with thepresent invention.

FIG. 2 is a schematic representation of a device for removing a toplayer of a surface covering by grinding.

FIG. 3 is a schematic drawing of a piece of equipment for heating asurface covering forming a channel in the surface covering, passing aconduit into the channel and filling the channel to cover the conduit.

FIG. 4 is a schematic representation of the shape of wheels for pressingthe conduit into the channel.

FIGS. 5 and 6 are sectional views of surface coverings aftermodification or retrofitting in accordance with the method of thepresent invention.

FIG. 7 is a schematic drawing showing conduits being placed in channelsformed in a surface covering in accordance with the present invention.

FIG. 8 is a sectional schematic drawing of conduits placed in channelsin a surface covering with a top layer covering the conduits and thehigh conductive layer at which the conduits are placed.

FIGS. 9 and 10 are schematic drawings of a surface covering havingchannels formed in the underside thereof with conduits placed in thechannels.

FIG. 11 is a schematic drawing showing conduits embedded in a surfacecovering after modifying or retrofitting of the surface covering.

FIG. 12 is a schematic drawing showing a guardrail with a base thermallycoupled with a roadway.

FIG. 12A is a sectional schematic drawing of a guardrail having athermal insulated outer coating to retain heat.

FIGS. 13, 14 and 15 are schematic/block diagrams of a system utilizing asurface covering retrofitted or modified in accordance with the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a schematic drawing of a retrofitted/modified surface coveringfor use of solar heat energy formed in accordance with the presentinvention. The surface covering has a top layer 2 and a lower layer 4and in order to form the surface covering, the top layer and middlelayer are ground away such that a network of conduits 50 can beinstalled in the recess formed by grinding. The network of conduits 50carry fluid to be heated and the network is installed in, on, under orin contact with all or a portion of the surface covering, preferably inthe layer 4 (or 14 as shown in FIGS. 5 and 6) which are high thermalconductivity layers.

The method of modifying an existing surface covering to embed conduitstherein to collect solar heat is shown in FIG. 2 where an existingsurface covering 7 is removed with a grinder 6 which can be part of apiece of equipment, such as equipment moved by a vehicle 5. Theequipment can be driven by an operator or could be a hand-driven pieceof equipment. The grinder 6 removes a portion of the existing surfacecovering 7 or the entire surface covering can be removed thereby forminga recess shown by the curved lines in FIG. 2 and the cut away portion inFIG. 1. Once the surface covering has been ground away, the network 50of fluid carrying conduits can be installed in the recess and part of aresurfacing operation for the surface covering.

As shown in FIG. 3, a method for modifying a surface covering includesthe step of softening the existing surface covering, for example by useof a heater 8, forming a channel in the softened surface covering, forexample by use of a wheel 9, pressing a conduit 11 into the channel, forexample with use of a wheel 13 having shaped peripheries as shown inFIG. 4 which illustrate U-shaped and V-shaped wheel peripheries andfilling the channel with thermal conductive material to cover theconduit, for example by means of a rotating spreader 15. The filler canbe obtained from the surface covering or can be another thermalconductive layer of material.

As shown in FIG. 5, the resulting structure includes fluid carryingconduits 11 embedded in the surface covering. The fluid carryingconduits can be embedded at different lengths within the covering withvarying spacing, and the fluid carrying conduits can be formed as asingle loop, for example running down the side of a driveway road orsidewalk or multiple loops covering the entire area of a surface. Thefluid carrying conduits are referenced as “heat exchanger pipes” in thedrawings and are shown disposed in a high thermal conductivity layer 14.An example of a high thermal conductivity layer is an asphalt binderwith high thermal conductivity aggregate therein increasing theefficiency of the surface covering in capturing heat from incident solarradiation on the covering. The high thermal conductive layer can be atany depth within the covering so as to be in the top low thermalconductive layer 16 and the bottom low thermal conductive layer 18. Thehigh thermal conductive aggregate can be created by additives such asmetal particles, wire, rods, rebar, conductive films or tapes as well asconductive aggregate (rock) materials such as in the class of quartziteand sandstone.

As shown in FIG. 6, the surface covering can have a top visibletransmitting and infrared/heat blocking layer on a low thermalconductive layer and the fluid carrying conduits 11 can be disposedbetween layers of asphalt 16 and 18 constituting low thermal conductivelayers. The surface covering can be created with a visible wavelengthlight transmitting and infrared heat blocking top layer with embeddedfluid carrying conduits but with no conductive layer and no lower heatinsulating layer. Alternatively, the surface covering can be made withno visible wavelength light transmitting, infrared heat blocking toplayer but with a thermal conductive layer and lower heat insulatinglayer. The purpose of the arrangement of the layers is to increase theefficiency of the system by allowing an increased percentage of heatenergy to be captured by fluid in the conduits from the incident solarradiation on the surface covering. The top layer creates the “greenhouseeffect” within the surface covering to allow light from the sun to enterthe surface covering while trapping heat therein whereby more heat canbe transferred to the fluid in the conduits 11 to drive a more efficientsystem. The top layer can be of a material type such as glass, ceramic,rock type materials, film, tape, a spray-on layer and liquid thathardens, for example.

FIG. 7 shows conduits 28 (11 in FIGS. 3-6) laid in channels 30 in asurface covering. Once the conduits are installed, the conduits can beleft as is covered with another layer or the channels can be filled witha solid, liquid or malleable material that subsequently hardens. Thefill material can be a high thermal conductivity material.

FIG. 8 shows conduits 28 in channels 30 in a surface covering where thesurface covering has a top layer of covering with an optional middlelayer 14 of higher thermal conductivity materials.

FIG. 9 shows positioning of the channels on the underside of a surfaceof the channels 30 on the underside of a surface covering with conduitsin the channels. This arrangement is particularly useful for roofingmaterials, such as shingles.

FIG. 10 shows conduits 28 in channels 30 on the underside of a surfacecovering in the form of a mat 32 that can absorb solar radiation butcould also absorb heat from a surface supporting the mat. Sloped edgesof the mat allow it to be used in an area where pedestrians or vehiclesmight pass such as on a roadway or parking lot. The ability to perform amat can provide cost savings over more permanent installed systems.

FIG. 11 shows conduits 28 embedded in surface covering 32 where the matcould be formed by extrusion with channels and separate conduits. Theability of mats and conduits to interlock in a leak-free seal increasesflexibility in system design. The bottom surface of the mat can beeither a thermal conductor to take heat from the surface supporting themat or a thermal insulator to prevent heat from escaping to the surfacebelow.

FIG. 12 shows a roadside guardrail 36 having a base 34 extending intothe surface covering or roadway for better thermal contact with thesurface covering. Fluid carrying conduits can also be embedded or formedin the guardrail to increase heat transfer. The guardrail is normallyformed of a metal-based thermal conductor and can be used to capture andtransport solar generated heat either with the fluid carrying conduitsor without the conduits. The concept of utilizing roadside heatcollectors can be extended to other common roadway structures such asdividers, Jersey walls and the like.

FIG. 12 b shows the guardrail 36 being surrounded with a thermalinsulated outer layer to retain heat. Other roadway metal structures canbe similarly insulated to assist in the capture and transport of solarthermal energy for example, bridges, overpasses, pipes and railroadtracks.

FIGS. 13, 14 and 15 show systems for operating energy conversionequipment, utilizing the heat and energy produced by surface coveringsmodified or retrofitted in accordance with the present invention. InFIG. 13, heat from conduits in a surface coating is supplemented by aconcentrated solar power system (CSP) and can also be used to store theCSP heated fluids at night to maintain higher temperatures. The systemis shown operating a steam cycle turbine 26. In FIG. 14, fluid carriedby conduits in a surface covering 20 obtained from solar radiationincident on the covering is supplied via a heat exchanger 24 to anauxiliary heater 32 to raise the temperature before supplied to anenergy conversion device (ECD) to convert the heat into a useful form ofenergy. The use of heat exchangers permits multiple circulating fluidloops to control temperatures, pressures and flow rates, and separatefluid storage tanks can be maintained. An optional cold source 44 cancreate a higher temperature differential for the ECD. FIG. 15 shows useof heat from solar radiation on a surface covering 20 with a heatexchanger 24 and auxiliary heater 32 as shown in FIG. 14 for operatingenergy conversion devices including hot water supply, chiller, heatpump, ORC (organic Rankine cycle), water purification and/ordistillation units. Additionally, conduits 30 can communicate with thesurface covering 20 to supply a fluid with increased heat through thesurface covering for melting of precipitation such as snow or ice. Forthis use, separate conduits 30 can be used or the conduits from the mainsystem can be run with the flow reversed. Multiple auxiliary heaters,such as solar concentrators 28, can also be used in the system.

As described above, high heat conductive aggregate in an asphalt binderimproves the heat transfer in a pavement or structure and, thus, usingmore conductive rocks, aggregate, can improve heat transfer in thesystem. Use of thermally conductive additives to a pavement or hotasphalt mix (HMA) could have a negative impact on binding and structure.In addition, the high cost of certain metal-type additives could makethem prohibitive as a conductive additive. Accordingly, the use ofaggregate itself as the conductive material instead of another thermallyconductive material that would not normally be part of the HMA orpavement is desirable.

As explained above, the surface covering has a high thermal conductivelayer disposed within the surface between low thermal conductive layersand can reduce the cost of what may be a more expensive aggregatematerial. This layer will also make it possible to increase efficiencyas the asphalt will conduct more heat through the layer and less energywill tend to be conducted inwards where it cannot be used.

The heat source from the surface covering can be used in conjunctionwith a system to produce cooling or air conditioning. Specifically thelow temperature heat source can be attached to an adsorptive chiller,absorptive chiller, heat pump or other systems that use a refrigerant,desiccant, or the like via a heat exchanger. A chilling system that usesexpanding gases to create a cooling effect can be fueled by heat. Thesesystems, including adsorptive and absorptive chillers, are designedspecifically to make use of low temperature heat sources and are oftenused for large scale cooling requirements. The heat that can begenerated from paved surfaces, buildings and rooftops, with averagetemperatures of 120-150 F are perfectly matched for these chillersystems. The heat is used to heat a fluid such as water or refrigerantthat is used in such systems.

Flexible pipes (conduits) can be used for collection of heat fromconstruction fixtures and buildings. Use of modern flexible pipingmaterials allows lower cost of installation and more durable systems.The pipe/conduit itself is used for heat transfer. The pipes areextruded in geometries favorable to heat transfer with the outsidemedia. Pipes extruded in different geometries such as with fins, oval,stars and the like promote better surface area and contact with themedia. Having a pipe cross section with more surface area towards thehorizontal plane will promote heat transfer since the top and bottom ofthe pavement are cooler than the center. That is, where an oval pipecross section is used, the longer leg is preferably disposed vertically.

An alternate method to embedding the pipe prior to paving is to installthe pipes in pavement prior to hardening of the pavement. Then the pipesare left exposed or are covered with an additional material. That is,the pipe gets pressed into the asphalt when it is still not hardened.This can be on a top layer or a middle layer. An asphalt roadway machinecan be designed to press the hose into the still soft asphalt.

A grinding/milling machine can be used to mill a pipe channel into asurface to create channels or grooves wherein the pipe can be laid. Thepipe is pressed into the channel, left exposed or covered with anadditional roadway layer, as required. This arrangement is particularlyeffective in low energy demand projects, like home heating and coolingand/or pool heating.

Solar thermal energy can be harvested without embedding pipes below thesurface. Materials are produced with internal pipes or channels tocreate a similar result. One design resembles a rubber speed bump withembedded grooves for the tubes, or a closed bladder, holding fluid abovethe surface, facilitating the easy placement and removal of the heatingtechnology. Similar designs with internal fluid carrying channels can beused in roofing materials (shingles), siding materials, and surfacingmaterials such as driveway or patio bricks or in surface composites(e.g. Trex, or Timberteck). Thermally conductive materials, lowemissivity coatings and interlocking channels are design featuresdependent upon use conditions. In the simpler version, the fluidcarrying channels are not within the materials, but grooves or channelsare manufactured into the front or underside of the surface. Then aflexible hose or pipe is pressed into the channel. An advantage of thisdesign is to limit the number of connections between panels, thuslowering the chance of a leak.

The system can collect heat from structures and buildings. The heatconductive materials used in municipal and traffic structures as well asbuildings provide a source to capture, store and transport heat energy.Existing heat-conductive structures in bridges, overpasses, guardrails,railroad tracks, and the like, can be used to collect and transportheat. The structures themselves gain heat from incident radiation andthey also act as a heat exchanger to pull heat from the paved surfacesand structures they are in contact with. Because of the thermalconductivity of these metal based structures, heat can be transported. Afluid based heat exchanger can be placed along the back of a guardrailor at periodic intervals. These structures include, but are not limitedto, metal guardrails, metal utility poles, road signs, bridges,overpasses, and railroad tracks. A design to promote heat exchangebetween the surfaces and the metal structures and to enhance thermaltransfer can include elongated footings added to guardrails to extendfurther into the roadway material. They provide additional contact areawith the adjacent paved surface which will promote heat transfer. Inanother design, the structures are thermally insulated to hold the heatwithin and allow it to transport within the body to the heat exchanger.In the design using a metal guardrail, elongated fins or feet canextract heat from the paved surface while the plastic or rubber coatedguardrail transports the heat within its metal structure to a heatexchanger.

The fluid carrying conduit of the system can be designed in a closedloop, where a heat exchanger is used to extract the heat. The heatexchanger is used to transfer heat from the fluid to a second fluid foruse in various systems, i.e., to have two independent fluid loops sothat the fluid that is used to collect the heat is kept separate fromthe working fluid used in the target system. Alternatively, the heatexchanger could be a radiator or similar structure to heat buildings(e.g., homes, hotels/motels, office buildings, etc.)

A heat exchanger between systems has several advantages including, butnot limited to, fluids made up of different materials and are managedfor different contaminants to add a longer life to the systems and allowfor easier maintenance.

The heating source described herein can be used to produce, or assist inproducing, clean or fresh water (desalination) and to reclaim andrecycle wastewater. Certain purification processes are achieved from lowtemperature heating of the water. Low grade waters are used forirrigation systems for crops and the like. Pasteurization temperaturesof 70° C. are achieved by the system. Clean water is becoming a scarceresource in some regions of the country and world. These systems will beused by governments or private property owners. In the Pacific southwestof the US, there are already shortages and rationing. Fighting for thelimited sources between agriculture, towns and cities is underway.Meanwhile, this is still one of the fastest growing areas for populationand construction of commercial and residential properties. Farms, lawns,golf courses and the like all have requirements for water. There aredifferences in water quality: potable, drinkable, for lawns, ponds,other uses. Further, desalination as a technology is important in areasof the world where fresh water is in short supply. The present heatsource can be used for water purification and desalinization in membranebased purification systems. The higher temperature water containsatoms/molecules in an excited state which allows for easier separationof the undesirable elements at the membrane filter. Easier separationresults in lower energy costs to push the fluid through the membrane. Afurther benefit is to keep the filters cleaner, preventing clogging,which allow a longer membrane filter life, lower energy costs and lower(less frequent) replacement costs.

Inasmuch as the present invention is subject to many variations,modifications and changes in detail, it is intended that all subjectmatter discussed above or shown in the accompanying drawings beinterpreted as illustrative only and not be taken in a limiting sense.

1. A method for modifying a surface covering to embed conduits thereinto collect solar heat energy comprising the steps of grinding away aportion of the surface covering to form a recess therein; installing anetwork of conduits for carrying heated fluid in the recess; and fillingthe recess to cover the conduits with a material capable of transferringheat from solar radiation to the conduits to heat the fluid.
 2. Themethod for modifying a surface covering to embed conduits as recited inclaim 1 wherein the surface covering is pavement and said filling stepincludes filling the recess with ground pavement.
 3. A method formodifying a surface covering to embed conduits therein to collect solarheat energy comprising the steps of forming a channel in the softenedsurface covering; pressing a conduit into the channel; and filling thechannel with thermal conductive material to cover the conduit.
 4. Themethod for modifying a surface covering to embed conduits as recited inclaim 3 wherein the thermal conductive material is obtained from thesurface covering.
 5. The method for modifying a surface covering toembed conduits therein as recited in claim 4 wherein said softening stepincludes heating the surface covering.
 6. The method for modifying asurface covering to embed conduits therein as recited in claim 5 whereinsaid softening step, said step of forming a channel, said pressing stepand said filling step are all accomplished by a piece of equipment movedalong the surface.